package com.mmall.concurrency.example.aqs;

import lombok.extern.slf4j.Slf4j;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;

@Slf4j
public class SemaphoreExample2 {

    private final static int threadCount = 20;

    public static void main(String[] args) throws InterruptedException {

        ExecutorService executorService = Executors.newCachedThreadPool();

        final Semaphore semaphore = new Semaphore(3);

        for (int i = 0; i < threadCount; i++) {

            final int threadNum = i;
            executorService.execute(()->{
                try{
                    if(semaphore.tryAcquire()){
                    test(threadNum);
                    semaphore.release();
                    }
                }catch (Exception e){
                    log.error("exception",e);
                }
            });
        }
        log.info("finish");
        executorService.shutdown();
    }

    private static void test(int threadNum) throws InterruptedException {

        log.info("{}",threadNum);
        Thread.sleep(100);
    }
}
